On Sept. 24, 2007, NRG Energy sought permission to build two reactors in Texas, the first such request since the 1970s. The Nuclear Regulatory Commission (NRC) last approved a new plant in 1978, and the last reactor came on line in 1996. Can nuclear power be the Michael Jordan of the energy world and come back? Or is the age of the atom over?

Strong arguments for and against nuclear renaissance exist. In a provocative piece in the New York Times Magazine on July 16, 2006, journalist Jon Gertner argued that “nuclear power in this country is dying … it will effectively be extinguished as an energy source by around 2050.” Reactor lifetimes, originally constrained by 40-year NRC licenses, are now being extended by 20 years. But unless things change (either new plants or further extensions), the curtain will drop on the American nuclear age: If all 104 operating reactors were granted 20-year license extensions, our nuclear array would still shut down by 2056.

Those who regard nuclear power as too expensive and dangerous would applaud. But what would fill the gap in the U.S. electrical power grid? Of the electricity generated each year in the United States, half comes from coal, 20 percent from nuclear, another 19 percent from natural gas, 7 percent from hydroelectric, a slim 3 percent from oil, and only 2 percent from wind, solar and other renewables, according to the Energy Information Administration. And energy demands are expected to double in the next couple of decades. Can conservation, alternative energy, increased use of fossil fuels or rekindled nuclear power fulfill our needs?

Many favor resuscitating the dying nuclear patient. In Nuclear Energy Now, energy experts Alan M. Herbst and George W. Hopley list the top misconceptions about nuclear power: (1) harmful to the environment, (2) too expensive, (3) not safe, (4) vulnerable to attack, (5) has an intractable waste problem, (6) is firmly opposed by public opinion and (7) employs technology that hasn’t evolved. They then surgically (but simplistically) destroy these premises, making a strong albeit flawed case to renew America’s nuclear power grid.

Others argue that the fossil fuel era must end because fossil fuels are too susceptible to global politics and economics (unreliable supplies) and environmental concerns (greenhouse gases). In The Bottomless Well, Peter W. Huber and Mark P. Mills, co-founders of ICx Technologies Inc. and venture capitalists, see nuclear power as “the one demonstrably practical technology that could decisively shift U.S. carbon emissions in the near term” and that it would finally “displace coal with uranium.”

Some countries have already jumped aboard the nuclear wagon. Europe is actually rebooting its nuclear program, spurred on by the cost of fossil fuels, anxiety over global climate change and the uncertainty of fossil fuel supplies. France leads the way, producing almost 80 percent of its electricity from nuclear plants. After the oil embargo of the 1970s, the French government made a calculated decision to go nuclear, convincing the public of the necessity in terms of economics and national security. Sweden, Italy and the Netherlands recently lifted plans to phase out old plants. Even Britain, searching for clean energy, has joined the queue.

However, others espouse the very concerns Herbst and Hopley try to alleviate. For example, just because terrorists haven’t hijacked a U.S. Navy nuclear-powered ship doesn’t mean nuclear power plants are secure. Also, uranium extraction is messy and expensive, and reserves are finite. Reactor byproducts have no permanent home and are vulnerable to the designs of terrorists and hostile governments. As Helen Caldicott, a medical physician and anti-nuclear advocate, writes in Nuclear Power is Not the Answer: Nuclear power is “not clean and green, [is] exorbitantly expensive, and [is] notoriously unreliable.” Furthermore, nuclear plants are costly and technologically complex.

In the end, cost may be the killer. Economics, together with the accidents at Three Mile Island in 1979 and Chernobyl in 1986, curbed our nuclear appetite. Nuclear plants cost twice as much in capital as coal plants, and more for gas plants. However, a carbon tax and mandatory limits on greenhouse gas emissions could significantly increase the overall competitiveness of nuclear plants.

My own indecision on the topic was resolved by reading the April 2007 report by Charles D. Ferguson, “Nuclear Energy: Balancing Benefits and Risks,” published by the Council on Foreign Relations. Ferguson makes many points moot by substituting realism for ideology. He puts a convincing lid on nuclear pipe dreaming. He convinced me that nuclear energy couldn’t grow fast enough to significantly improve energy security or counter global climate change. Rapid building and fueling of nuclear power plants would overwhelm our manpower and capital. The precipitous falloff in active U.S. reactors is unavoidable. Do the math: To replace 100 reactors in the next four decades means adding one reactor every four to five months — unrealistic if the past three decades are any guide. Furthermore, if we were to substitute nuclear power for fossil fuels over the next couple of decades, we would need to have between 2,000 and 3,000 gigawatts of nuclear capacity — the world currently has only 370 gigawatts of nuclear power capacity. Reaching such a goal equates to building a new reactor each week worldwide for four decades. Landing on the moon was easier!

Schwab is a professor of geology at Washington and Lee University in Lexington, Va. E-mail: schwabf@wlu.edu.